$1,171,000.00
Yes, that is the real answer given your exact stipulations. I built an Excel spreadsheet to come up with the answer. You made a mistake in your OP. You need about $160,000 a year to match $50,000 a year now given 3% constant inflation. Also note that my number is correct mathematically speaking but it is way too low for the real world. You could easily see a less than 6% or even a negative return during the early years and that destroys the whole model.
Seed Money
$1,171,000.00
Year Spending per Year Investment Remaining
1 $50,000.00 $1,121,000.00
2 $51,000.00 $1,138,260.00
3 $52,020.00 $1,155,555.60
4 $53,060.40 $1,172,868.94
5 $54,121.61 $1,190,180.67
6 $55,204.04 $1,207,469.90
7 $56,308.12 $1,224,714.06
8 $57,434.28 $1,241,888.78
9 $58,582.97 $1,258,967.82
10 $59,754.63 $1,275,922.93
11 $60,949.72 $1,292,723.67
12 $62,168.72 $1,309,337.37
13 $63,412.09 $1,325,728.90
14 $64,680.33 $1,341,860.54
15 $65,973.94 $1,357,691.84
16 $67,293.42 $1,373,179.42
17 $68,639.29 $1,388,276.76
18 $70,012.07 $1,402,934.08
19 $71,412.31 $1,417,098.06
20 $72,840.56 $1,430,711.63
21 $74,297.37 $1,443,713.77
22 $75,783.32 $1,456,039.23
23 $77,298.98 $1,467,618.26
24 $78,844.96 $1,478,376.37
25 $80,421.86 $1,488,233.99
26 $82,030.30 $1,497,106.17
27 $83,670.91 $1,504,902.24
28 $85,344.32 $1,511,525.47
29 $87,051.21 $1,516,872.67
30 $88,792.23 $1,520,833.82
31 $90,568.08 $1,523,291.62
32 $92,379.44 $1,524,121.04
33 $94,227.03 $1,523,188.86
34 $96,111.57 $1,520,353.16
35 $98,033.80 $1,515,462.78
36 $99,994.48 $1,508,356.74
37 $101,994.37 $1,498,863.67
38 $104,034.25 $1,486,801.12
39 $106,114.94 $1,471,974.94
40 $108,237.24 $1,454,178.49
41 $110,401.98 $1,433,191.97
42 $112,610.02 $1,408,781.50
43 $114,862.22 $1,380,698.37
44 $117,159.47 $1,348,678.05
45 $119,502.66 $1,312,439.26
46 $121,892.71 $1,271,682.96
47 $124,330.56 $1,226,091.23
48 $126,817.18 $1,175,326.14
49 $129,353.52 $1,119,028.53
50 $131,940.59 $1,056,816.72
51 $134,579.40 $988,285.13
52 $137,270.99 $913,002.84
53 $140,016.41 $830,512.02
54 $142,816.74 $740,326.33
55 $145,673.07 $641,929.18
56 $148,586.53 $534,771.86
57 $151,558.26 $418,271.63
58 $154,589.43 $291,809.67
59 $157,681.22 $154,728.82
60 $160,834.84 $6,331.33